A Radio Frequency Identification (RFID) consists of an RFID reader, RFID tag, and information managing host computer. The detailed techniques for different frequencies like low frequency (125 KHz), high frequency (13.56 MHz) and super high frequency (2.45 GHz) are discussed. TAG (Transponder) design techniques are also discussed in this book. RFID is extremely fast and extremely accurate and how RFID can reduce the work of labor which will be implemented by some applications.